In this paper, we study a class of damped vibration systems, u¨(t)+Bu˙(t)−L(t)u(t)+∇W(t,u(t))=0,∀t∈R,(Formula presented.) where (Formula presented.) is of indefinite sign. By using a critical point theorem of Ding, we establish a new criterion to guarantee that the above system has infinitely many nontrivial homoclinic orbits under the assumption that (Formula presented.) is asymptotically quadratic or subquadratic as (Formula presented.). Recent results in the literature are gene...
